The Grumman J2F Duck (company designation G-15) was an American single-engine
amphibious biplane. The J2F was an equal-span single-bay biplane with a large
monocoque central float which also housed the retractable main landing gear. It
had strut-mounted stabiliser floats beneath each lower wing. A crew of two or
three were carried in tandem cockpits, forward for the pilot and rear for an
observer with room for a radio operator if required. It had a cabin in the
fuselage for two passengers or a stretcher.

The Duck's main pontoon was blended into the fuselage, making it almost a flying
boat despite its similarity to a conventional landplane which has been
float-equipped. This configuration was shared with the earlier Loening OL,
Grumman having acquired the rights to Loening's hull, float and undercarriage
designs. The aircraft was used by both the United States Navy and United States
Coast Guard, with the latter using them as utility aircraft for missions
including mapping, rescue work, photography, and a target training.